The first I.S. machine was patented in U.S. Pat. Nos. 1,843,159, dated Feb. 2, 1932, and 1,911,119, dated May 23, 1933. Today more than 4000 I.S. machines, manufactured by a number of companies, are in use worldwide, producing more than a billion bottles every day of the year. An I.S. (individual section) machine has a plurality of identical sections (a section frame in which and on which are mounted a number of section mechanisms) each of which has a blank station which receives one or more gobs of molten glass and forms them into parisons having a threaded opening at the bottom (the finish) and a blow station which receives the parisons and forms them into bottles standing upright with the finish at the top. An invert and neck ring holder mechanism which includes an opposed pair of arms, rotatable about an invert axis, carries the parisons from the blank station to the blow station inverting the parisons from a finish down to a finish up orientation in the process. A bottle formed at the blow station is removed from the section by a takeout mechanism.
The blank station includes opposed pairs of blankmolds and the blow station includes opposed pairs of blowmolds. These molds are displaceable between open (separated) and closed positions. Opposed pairs of neck ring molds, carried (supported proximate their tops) by the invert and neck ring holder mechanism, define the finish of the bottle and hold a formed parison as it is transferred from the blank station to the blow station.
The blankmold is open at the top and a track delivers a gob by gravity down to a position vertically above the open mold. Where the bottle to be formed is not circular in cross section (square for example) a funnel, which has a square passage, can be displaced into position over the open top of the blankmold to direct the gob into the mold, slightly changing its shape in the process. With the gob in the blankmold, a baffle of a baffle mechanism can be displaced down onto the funnel to supply air under pressure, through a number of exposed holes, to the blankmold to "settle" the gob in the blankmold. The funnel and baffle are then removed and the baffle is repositioned on top of the open blankmold. The settle blow holes are now closed. Now, either counterblow air is introduced into the mold to blow the gob into the mold (a blow and blow machine) or a plunger is advanced to press the gob into the mold (press and blow machine). Air trapped between the outer surface of the gob and the inner surface of the blankmold will be forced out suitable notches in the bottom surface of the baffle. When the parison has been formed, the baffle will be removed, the blankmold will be opened, and the parison will be transferred to the blowmold. When a gob doesn't have to be shaped, the funnel may be dispensed with and the baffle may be immediately positioned on top of the blankmold to start the settling process. In a state of the art baffle of this type, a central piston hangs from the bottom of the baffle to define a large central opening for settle air. When counterblow occurs the upward movement of the gob engages and pushes this piston upwardly to its home position where the bottom of the piston is flush with the bottom surface of the baffle and a small annular groove exists between the piston and the bottom of the base through which air can continue to escape from the blankmold through the baffle. Bottles made in this way have a visible circular ridge on the bottom of the bottle and this is undesirable.